kernel timer frequency question

Leigh · 2008-10-31 17:50:19

I use hydrogen and rosegarden quite often to alter and compose drum sequences to use while playing the guitar. In my custom kernel config I set kernel timer frequency...
CONFIG_HZ_1000=y
CONFIG_HZ=1000

instead of the standard...
CONFIG_HZ_300=y
CONFIG_HZ=300

Is there any dissadvantage to using using timer frequency CONFIG_HZ=1000? Perhaps some ill effects in the long term?

I'm having trouble finding some detailed info on this.

bangkok_manouel · 2008-10-31 17:58:33

Leigh wrote:

CONFIG_HZ_1000=y
CONFIG_HZ=1000

is the recommended setting for desktop computers so you don't have to be worried about anything I suppose.

Evanlec · 2008-11-03 03:47:37

afaik 300hz or lower frequencies will give you better throughput, so things like compiling, video encoding, compressing, will be faster.

At 1000hz the system is more responsive, but spends a lot of time 'waiting' for events (so it can respond to them quickly), so your throughput is less.

This is my limited understanding, and it may not be correct ;p

Leigh · 2008-11-03 16:44:36

That makes sense, and would explain why arch's default kernel uses 300hz. I spent a lot of time googling to try and understand better, but I havent found anything explaining the pros and cons of using a higher timing hz. I did read some info about people trying to use 2000hz and having issues. That seemed a little extreme to me.

Evanlec · 2008-11-03 23:44:10

yea i noticed the same when i tried looking for info about it.
its one of the reasons a lot of ppl are using 1000hz these days and not realizing the disadvantages

shazeal · 2008-11-04 00:22:23

1000hz is for Single core machines. 300 should be used on dual core, as the timer is per core, so a setting of 1000hz will give an actual timer of 2000hz. The Zen kernels tweak these values to ~430, ~860 and claim that these are the optimal settings.

Leigh · 2008-11-04 10:07:19

Thanks, this makes much better sense now, but even though I have a dual core, Rosegarden will complain that the timing frequency is too low when I use the default kernel configured at 300hz.

Rosegarden is happy with my custom kernel configured at 1000hz. I just checked the zen kernels configs in aur, they seem to be using 1000hz as default, but they have 432hz and 864hz commented out. I'll try rebuilding with lower values starting with 432hz to find a happy medium and still keep Rosegarden happy.

4internetanonymity · 2019-12-13 10:52:44

shazeal wrote:

1000hz is for Single core machines. 300 should be used on dual core, as the timer is per core, so a setting of 1000hz will give an actual timer of 2000hz. The Zen kernels tweak these values to ~430, ~860 and claim that these are the optimal settings.

I don't see where the zen kernel is using 860... I though Liquorix was the maintainer of the Zen kernel, and on their forum they say 1000hz:
https://techpatterns.com/forums/about24 … t=confighz

Slithery · 2019-12-13 10:57:18

4internetanonymity wrote:

I don't see where the zen kernel is using 860... I though Liquorix was the maintainer of the Zen kernel, and on their forum they say 1000hz:
https://techpatterns.com/forums/about24 … t=confighz

Things do change in the 11 years since this thread was started.

Putting this back to sleep for good...

Arch Linux

#1 2008-10-31 17:50:19

kernel timer frequency question

#2 2008-10-31 17:58:33

Re: kernel timer frequency question

#3 2008-11-03 03:47:37

Re: kernel timer frequency question

#4 2008-11-03 16:44:36

Re: kernel timer frequency question

#5 2008-11-03 23:44:10

Re: kernel timer frequency question

#6 2008-11-04 00:22:23

Re: kernel timer frequency question

#7 2008-11-04 10:07:19

Re: kernel timer frequency question

#8 2019-12-13 10:52:44

Re: kernel timer frequency question

#9 2019-12-13 10:57:18

Re: kernel timer frequency question

Board footer